High-pressure freezing is a cryopreservation technique that was developed as a means for preserving ultrastructure in electron microscopy. Many of the traditional protocols used for fixing and staining samples for the light microscope give poor preservation of structures in the cytoarchtitecture such as actin filaments in the cell cortex. We will investigate whether high-pressure freezing can give improved specimen preparation for the light microscope. We will high-pressure freeze samples C. elegans embryos and then freeze substitute with methanol or acetone. The embryos will then be brought up to ambient temperature and immunostained for actin and tubulin using conventional protocols. We will asses the preservation of the actin and tubulin networks in early embryos and compare high-pressure frozen samples with samples that have been prepared without this step. We will specifically examine critical actin filaments and microtubules in the mitotic spindle.